Such a hub is organised so that for each segment or repeater conflict between transmissions is resolved by a carrier-sense multiple access technique, which is well established in the art and is the essence of an `Ethernet` communication system. A station wishing to transmit will first detect whether there is a carrier signal present in the segment to which it is connected and will either not transmit or will wait until an end of transmission is detected and then transmit its signal packet.
It is known that a system which resolves signal contention in this manner is subject to difficulties in conditions of heavy loading. This is particularly true for an Ethernet hub wherein, for example, there is signal traffic between stations connected to different segments which are connected via a bridge, because traffic is then subject to a plurality of possible contentions.
Multi-segment hubs of this character commonly include an internal switching matrix by means of which any port can be connected to any segment. It is therefore possible to contemplate measuring the traffic across the ports and controlling the connections so as to equalize the traffic across the segments. One such technique computes the volume of traffic through each segment in a given period of time and reallocates the ports connected to those segments to provide, so far as possible, an equalization of the traffic through the segments.
One disadvantage of such a technique known as octet-based load balancing, is that there tends to be a dispersal of end stations within a work group, so that forms an initial condition, wherein a multiplicity of stations forming a work group are connected to the same segment, at least some of the stations in such a work group have their ports associated with different repeaters. It will thus be apparent that there is a high likelihood that a given packet will appear on two segments, that is to say the segments connected via respective ports to the source and destination of the packet, and therefore the traffic across the bridge between segments remains high.